Aeronautical engine



1943. c. c. DE PEW AERONAUTICAL ENGINE I Filed Sept. 24, 1940 3 Sheets-Sheet 1 INVENTOR' CHESTER C. DE PEW 7 RNEY 5 Sheets-Sheet 2 c. c. DE PEW AERONAUTICAL ENGINE Filed Sept. 24, 1.940

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AERONAUTICAL ENGINE Filed Sept. 24, 1940 s Sheets-Sheet s INVENTOR Ticlja. CHESTER c. DE PEW menu June 29, 1943 2,323,231 I AmoNAU'rrcAL ENGINE. I

Chester 0. De Pew, Farmingdale, N. Y., assignor 'to' Fairchild Engine and Airplane Corporation,- Farmingdale, N. .Y., a corporation of Maryland Application September 24, 1940, Serial No. 358,070 (Cl. 123-171) 3 Claims.

This invention relates to internal combustion engines, and has particular reference to engines for aeronautical application, although the invention is not limited to that use.

Engines used for aeronautical purposes are customarily arranged so that the propeller shaft is either an extension of the crankshaft of the engineor is arranged parallel thereto and connected thereto by gearing. Because of the radial projection of the cylinders and valve gear of-radial engines, the visibility adjacent the propeller shaft is poor in single motor craft, requiring the pilot to be seated sufficiently high that he can see over thecowling around the engine. "Where in-line engines are employed, they are usually inverted in order to increase visibility and keep the center of gravity of the power plant lowfand for other reasons, but because of their length the fuselage and cowling is disproportionately long, so that the pilot in single motor craft is positioned a substantial distance behind the propeller, thus decreasing downward visibility in many types of craft while improving forward visibility, as compared to the radial engine. In either case, the space requirements for the engines is considerable. In the case of a conventional outboard drive, the driving mechanism is not only complicated and expensive, but considerably increases the weight of the power plant. In addition to these objections, the cooling of the usual engines, where they are air-cooled, is diflicult and complicated, and it is necessary to conduct the cooling air over long and devious paths, with the result that all .cylinders are not supplied with the same volume or temperature cooling air,

and some of thecylinders must be cooled by air already heated by other cylinders.

that the crankshaft thereof extends vertically, and is connected by simple bevel type gearing to a horizontal propeller shaft. The horizontal propeller shaft may be directed either forwardly or rearwardly to adapt the engine to tractor or pusher type aircraft. The engine so mounted on end is enclosed in cowling having one or'more large intake openings leading cooling airfrom the air stream directly to each individual cylinder, all of which are equal distances from the air intake opening by reason of the vertical'arrangement of the cylinder bank, whereby eac of them receives the same volume and temperature cooling air. Furthermore, the crankshaft is readily accessible from the front of the engine and the camshaft is likewise readily accessible from the rear with equal accessibility forinspection and repair of the mechanical and electrical accessories and equipment.

It will be seen that by reason of the arrangement of the engine on end, the space occupied thereby is small, thus enabling the engine to be utilized conveniently and effectively for outboard purposes, either on the fuselage or wing, and the mounting means for the engine is simple, involving merely a, supporting frame of small area and suitable bracing to the longerons of the fuselage or the spars of the wing, depending upon the position of the mounting of the engine. Although the invention is particularly adapted to use as an aeronautical engine, it is to be understood that it may be utilized with equal facility for air propulsion of land or water craft, since it can be mounted as readily on such craft as on airplanes,

In accordance with this invention, an internal combustion engine particularlyv adapted for aeronautical use is provided, which eliminates many of the aforementioned objections to aeronautical engines of' usual arrangement and design, and

provides many additional advantages'in so far asspace-saving, reduction of expensive and complicated gearing and mounting arrangements. and consequent weight saving are concerned, and providing greater accessibility for inspection and repair, simple and easy installation and dismounting. more efiective and eflicientcooling by air. decreased wind resistance, and improved visibility in all directions in single motor craft. because it enables the positioning of the In a prefer red embodiment of the invention, an m-hne engine is utilized and is so arranged having the same advantages as an outboard motor for those purposes.

For a more complete understanding of the invention, reference may be had to the accompanying drawings, in which:

Figure 1 illustrates in side elevation an in-line aeronautical engine mounted and arranged in accordance with the present invention, shown with the side panel of the cowling removed;

rangement therefor.

- piot closer to the propeller or nose of the craft.

Fig. 21s a front elevation of the same; Fig. 3 is a plan view thereof; Fig. 4 is a tranverse section therethrough as seen along the line 4-4 of Fig.2; and

Fig. 5 is a fragmentary vertical section through the engine as seen along the line 5-5 of. Fig. 4 and illustrating the preferred air-cooling ar- Referring to the drawings, numeral l0 designates an in-line aeronautical engine having a crankshaft housing H, camshaft housing, and a bank of interposed cylinders l3 comprising the the, forward thrust to cylinder barrels l4 and cylinder heads it, provided with heat radiating fins, as shown. The particular engine illustrated. has six cylinders 13 in line, but it isto be understood that the number of cylinders or their arrangementis immaterial and that it is also immaterial whether the engine has one bank of cylinders or is of the V, X, H,

radial, or other construction. The engine I is supplied with fuel-air mixture through the intake lubricating supply systems and of the accessories and auxiliary equipment and the like. Suitable air intake opening 34 is formed by a flange 38; which preferably constitutes an extension of the side wallof the cowling 28, as shown particularly compression braces 28 diagonally arranged in elevation and plan, as shown respectively in Figs.

1 and 3, are bolted or otherwise secured at one end to brackets 2| on the crankshaft case i I, and at their other ends to the supporting structure 19. These braces participate in-the absorption of the rearward thrust of the propeller and otherwise brace the engin rigidly on the supporting structure is, which may be part ofthe fuselage structure, such as the longerons thereof, or the wing structure, such as the spars or box girders thereof, when the engine is mounted plane.

Supported on the crankcase II and rigidly secured thereto is a gear box 22 having horizontal bearings 23 inwhich the horizontal shaft 24 of the propeller 25 is joumalled. The propeller shaft 24 bevel gear 21 secured on the end of the crankshaft of the engine I 0. It will be observed that propeller shaft 24 imparted by the bevel gearing 28, 21 is partially counterbalanced by the rearward thrust of the propeller 25, through suitable thrust bearings, not shown.

on an air- By properly proportioning the sizes of the bevel gearing 26, 21, any desired speed ratio of engine to propeller may be obtained.

As shown particularly in Figs. 2 3 and 4, the entire engine III is enclosedin a cowling 28, which as seen in plan, is streamlined so as to reduce wind resistance. This cowling is suitably secured at its forward end to abutments 29 on the gear box 22 and crankcase II, at its sides to suitable brackets 30 mounted on the camshaft housing I2 01 the engine l0, and at its rear end to a bar 3| extending upwardly from the supporting structure l9, as shown in Fig. 1. I The cowling 28 is made sectional for ready removal by removing the fastening screws 32 connecting it to 23, 38 and 3| or by hinging the sections and latching them shut by suitable separable fastener means, such as conventional cowling fasteners. The upper end of the cowling 29 is closed by a plate 33, likewise readily removable for access to the engine. The lower side ofthe cowling is also preferably closed at the base plate I 8, so that the entire engine is sealed in a chamber formed by I the cowling.

Positioned in the area developed by the propeller 25 is an air intake opening 34 in the cowling 28, as shown in Fig. 2, this opening being preferably positioned at the exhaust side of the engine, as shown, although it may be positioned on the intake side thereof, de

of maximum air blast carries a bevelgear 23 meshing with a in Fig. 4.

The intake opening 34 leads to a chamber 48 formed between the flange 35 and cowling 28 on one side, at the rear by a transverse vertical plate 36 spanning the space between the cowling 23 and the camshaft housing l2 and extending to the full height of the cylinder bank between upper and lower horizontal plates 31 and 38, respectively, as is shown in Fig. 5, and at the opposite side of the intake opening '34 by a plate 33 extending substantially parallel to the flange 35 and connected to the crankcase H and extending the full height of the cylinder bank between upper and lower plates 31 and'38. It will be observed that all of the air entering the intake opening 34 is confined within the chamber 48, which accordingly acts as an air scoop directing the air upon and between the barrels l4 and heads I8 of the cylinders l3 for cooling the same.

It is preferable to cool the engine by air under pressure and to that end there are interposed in the intercylinder spaces on the intake side of the cylinder bank a, series of curved baiiies 4|, preferably held in' place by clips 42 hearing against the cylinder barrels I 3 on the exhaust 'side of the engine and connected to the battles 4| by springs 43 or the like. The bafl'ies 4| extend .the full height of the cylinder barrels l 3, as shown in Fig. 4, and substantially close the inter-cylinder spaces except for the narrow passages remaining between the cylinder barrels, the edges .of the baiiies 4| and the horizontal surfaces of passages alongthe end cylinder heads and barrels.

The gross area of ,these restricted passages between the cylinders l3 and between the end cylindam and extensions or ends 31' and 38' is considerably less than the area of the air intake opening 34, so that the high velocity air stream entering intake opening 44 is trapped within the chamber 43 and builds upa substantial static air pressure. By reason of this substantial static air pressure within the air chamber 40, the

air flows at considerable velocity through these restricted passages adjacent the cylinders l3, so as to confine the air flow under pressure to the areas of the cylinders and heads which require most cooling.

The heated spent cooling air issuing from these passages adjacent the cylinders i3 discharges and e pands into the chamber 41 formed on the intake side of the cylinder bank within cowling 28. The corresponding side wallof the cowling 28 is provided with a vertical slot 48 forming an exit gill for the spent cooling air from the chamber 41. As shown in Fig. 4, the exit gill 48 is located behind the widest part of the cowling 28, resulting in the induction of a suction through between chambers 40 and 41. This cooling arrangement for the engine of this invention is preferred, although it is to be understood that the entire engine, with the exception of that portion enclosed within chamber 40, is placed under a separate volume of air under pressure, and the exit gill 48 is directly connected to a housing enclosing the low pressure side of the cylinders l3 for conducting the spent cooling air to atmosphere through gill 58. a

In operation, theengine drives the propeller 25 directly through the .bevel gearing 26, 2'! and propeller shaft 24. The air stream induced by the propeller and by the motion of the aircraft is partly diverted into the intake opening M and builds up a substantial static pressure within the air chamber Iii, in the manner described. Because each of the cylinders I3 is arranged an equal distance from the source of the air entering the opening 34, each cylinder is supplied with the same volume of air at the same temperature so that no cylinders are inemciently cooled by air previously used to cool other cylinders. Even where static air pressure cooling of the type described is not used, but instead, the air flow is conducted directly from the air intake opening through the inter-cylinder spaces with little or aircraft merely by turning the propeller shaft rearwardly and extending it to clear the cowling. or by merely reversing the hand of the propeller, the cooling air flow remaining unchanged.

While av preferred embodiment of the invention has been illustrated and described herein, it is to be understood that the invention is not. limited thereby, but is susceptible of changes in form and detail within the scope of the appended claims.

I claim:

1. In a cooling system for engines having at least one inline bank of spaced apart cylinders on a crankcase; the combination of a housing of substantially airfoil cross-section enclosing said engine, said housing having an opening in its leading edge substantially parallel with the iongitudinal axis of said crankcase and substantially I coextensive in length with said bank of cylinders,

means in said housing forming an air scoop ieading from said opening to said bank of cylinders and sealed from the remainder of said housing,

' means restricting the spaces affording air flow no obstruction by bailling, such as baifles ll, the

cooling action is highly efficient in the engine of this invention, since each cylinder is located equidistant from the air source, and is supplied with the same temperature and volume of air as. the other cylinders.

It will be seen that by reason of the vertical arrangement of the engine the space require ments for the engine are much less than for other engines, and the short fore and aft dimension of the engine permits it to be mounted closer to the aerodynamic axis of the aircraft without impairing the pilots visibility in single motor craft. For all types of craft, .the vertical arrangement of the engine of this invention enables it to be so mounted that it extends wholly or substantially wholly from the structure ofthe craft that it propels, i. e., an outboard motor, rendering it readily accessible for maintenance and repair.

Also, because of the vertical arrangement, the simple bevel driving gearing illustrated and described is sufllcient, thus eliminating complicated driving mechanism and proportionately reducing the weight of the power plant. Also, by reason of the arrangement of the vertical engine it.

presents a small wind resistance area, thus increasing the efllcacy of'the-entire craft and enabling advantageous designs not heretofore possible. It will be observed that the engine of this invention may be readily adapted to pusher yp between said cylinders to a gross area less than the area of said opening, and means forming an opening in said housing on the lee side of said cylinders exterior of said air scoop, for withdraw-g ing air heated-duringpassage between said cyl- -inders from said housing.

2. In a cooling system for engines :having at least one inline bank of spaced apart cylinders on a crankcase; the combination of a housing of substantially airfoil cross-section enclosing said engine, said housing having an opening in its leading edge adjacent to and substantially parallel with the longitudinal axis of said crankcase and substantially coextensive inlength with said bank of cylinders, means in said housing forming an air scoop leading from saidQopening to said bank of cylinders and sealed from the remainder of said housing, means restricting the spaces affordingjair flow between said cylinders to a gross area less than the area of said opening, and

means forming an opening in said housing on the lee side of said cylinders exterior of said air scoop; for withdrawing air heated during passage between said cylinders fromsaid housing.

3. In a cooling system for air-cooled engines having at least one inline bank of spaced apart cylinders on a crankcase; the combination of a housing of substantially airfoil cross-section enclosing the entire engine with the leading edge of said housing parallel with and adjacent to said crankcase, an opening in. the leading edge of said housing substantially coextensive in length with said bank ofcylinders and substantially parallel to the longitudinal axis of said crank- -case, means forming an air scoop leading from said opening'tosaid bank ofcylinders and sealed from the remainder of the housing, means restricting the spaces ail'ording air flow between the cylinders to a gross arealess than said opening, and means communicating with the interior .of the housing on the lee side of the cylinders for withdrawing air heated during passage between the cylinders from said housing.

CHESTER. C. DE FEW. 

